Ignition device for internal



Jan. 11 F. DVAUVSYINGER Y 2,3 3 5 mfiI'TIoN nEvicE' FOR I N'L znamu;'conlusu'snoiq mamas Filed March 5. 1940 a I nvent, v

V Alia/wax Patented Jan. 11, 1944 IGNITION DEVICE FOR. INTERNAL COMBUSTION ENGINES,

Franz Dausinger, Stuttgart, Germany; vested in the Alien Property Custodian Application March 5, 1940, Serial No. 322,387 In Germany March 24, 1939 3 Claims.

switching devices for controlling the firing or ignition point in the cylinders of the engine. In order to avoid 'the disturbances produced by wear of the mechanical contacts, it has been suggested already to replace the mechanical switching devices by electrical means, i. e., by gas discharge tubes acting as control valves. In practice, however, it was found diflicult to carry out this proposal, because neither the ignition voltages of various tubes of thesame type nor the voltages of the sources of current used for the supply of ignition devices for internal combustion engines are sufflciently constant. It has been attempted to avoid this drawback, at least with tubes comprising control grids, by the provision of a grid bias which changes in the ignition point, but in this case,'m'echanically operated switching means were again required for connecting the control voltage to the grid and for disconnecting it therefrom. Such switch means, of course, are electrically relieved, since they do not carry the working current, but still they'show the inherent del'ects of any mechanically operated switch.

It is an object of the invention to provide means for eliminating this-defect of the known ignition devices comprising gas-discharge tubes.

With this and further objects in view, asmay become apparent from the within disclosures, the

invention consists not only in the structures here.

in pointed out and illustrated by the drawing, but includes further structures coming within the scope of what hereinafter may be claimed.

The character of the invention, howeven may be best understood by reference to certain of its structural forms, as illustrated by the accompanying drawing in which- Fig. l is a circuit diagram of a tour-cylinder internal combustion engine having the invention appliedthereto.

Fig. 2 is a diagram showing the voltage conditions in the ignition device and Fig. 3 is a diagrammatic view of an impulse generator for use in connection with theinvention. 1 i

The invention contemplates the provision in the tube circuit of an impulsegenerator which produces a voltage impulse tor igniting the gas discharge tube in the firing-point. This impulse generator may be interpolated in the plate cir-- cult where a gas discharge tube is used having This invention relates to electric ignition detwo electrodes only, or in the grid circuit of a grid-controlled gas discharge tube. r

Referring now to the drawing in greater detail, and first to Fig- 1, it will be seen that one pole 5 of a source of alternating current a is connected to the anode c of a gas discharge tube e, through the primary b ofan ignition coil, b, i, while the other pole is connected to the cathode d thereof. The grid I of the tube e is negativelybiassed by the voltage of a storage battery 9 to block the tube against the passage of current from the source 0.. Moreover, an alternating current generator h is interconnected inthe grid circuit which generates voltage impulses having a very steep wave front, at a frequency corresponding to the ignition frequency, said impulses being superposed on-thenegative grid bias. With each voltage impulse Eh generated by the impulse generator h the bias E0 is reduced to an amount which is lower than the critical grid voltage E' indicated'by the hatched surface and varies with the working conditions, so that the tube e is not blocked any more by the grid bias. The anode voltage Ec is thereby reduced to the burning voltage of the tube, (which is the characteristic voltage of the ionised gas path) whereby an anode current and a current through the primary b of the ignition coilb, i,- is caused which in turn induce a voltage in thesecondary 80 i or the ignition coil applied to the spark plugs l,

through a distributor 10., As a result, an ignition spark Jumps over at the spark plugs 1. After the current has passed through zero, the tube is' blocked again by its bias. I

It will be understood that in place of the direct current, voltage derived from the storage battery 9, for example, an, alternating current voltage having a certain phase displacement with respect to the voltage of the source of alternating 40 current a and having an impulse voltage superimposed on it may be applied to the grid f of the tube e.

While any suitable impulse generator maybe used on principle to produce the voltage impulses Eh which are superimposed on the grid bias, I have shown a particularly suitable and simple device in Fig. 3,in which a permanent magnet m v is fixedly mounted'on a shaft m which rotates in synchronism with the crank shaft of the internal combustion engine.

A coil 0 is wound upon an iron core n and inserted, for example, in the grid circuit of the tube e, at h. It will thus be understood that a voltage impulse Eh is induced in the coil 0 with each change of the direction of the lines of magnetic force produced by the rotating magnet and passing through the coil 0, whereby the tube e is ignited. Where a magnet m havingone pair of poles is used, two changes of the direction of flux occur in the magnetic circuit of the coil with each Iuli revolution 01' the shaft m and, as a result, two voltage impulses are produced per revolution. Therefore, in case of a four cylinder engine, the impulse generator shown in Fig. 3 should be driven with the speed of the crank shaft of the engine. On the other hand, where a magnet m having two pairs of poles is employed in a four cylinder engine, the impulse generator may be driven with the speed of the control shaft, the same as the shaft of the ignition distributor is.

In some instances it may be useful to provide a speed-controlled device for adjusting the ignition point, of known type. in the drive of the alternating current generator a or in the drive or the impulse generator, or where the impulse generator and the source 01' alternating current are constructed as an integral unit, in the common drive for the two devices. Such devices for adjusting the ignition point are indicated at V k in Fig. 1, by dash and dot lines.

The method and apparatus 01' the present invention have been described in detail with re!- erence to specific embodiments. It is to be understood, however, that the invention is not limited by such specific reference but is broader in scope and capable 0! other embodiments than those specifically described and illustrated in the drawing. More particularly, the invention is not restricted to the use of an ignition plant fed by alternating current. For example, a thyratron circuit producing relaxation oscillations may be used instead, comprising a condenser which is charged from a source of direct current and discharged in the ignition point of the engine through a valve and an ignition transformer. Also in this case the impulse for the discharge may come from an impulse generator interpolated in the anode or grid circuit oi the gas discharge tube.

I claim:

1. In an electric ignition device for internal combustion engines, a source of ignition current. a gas discharge tube acting as acontrol valve for said ignition current, a circuit including said tube for controlling the operation or said tube, a bias potential, means for applying the bias potential to such control circuit to render said tube normally inoperative to pass said ignition current, and an impulse generator, comprising a magnetic circuit including a movable permanent ma net and a coil in which impulses are generated by movement of said magnet, in series with said bias potential, adapted cyclically to produce voltage impulses in said control circuit to permit said tube cyclically to pass said ignition current.

2. In an ignition system for internal combustion engines, a source of ignition current, an electron discharge tube acting as a control valve for said ignition current, said tube including a grid. a grid circuit operatively connected to said grid to supply a potential thereto, and control means in said grid circuit for controlling the potential on said grid to normally render the tube inoperative to pass ignition current therethrough but said control means being operable to'vary the potential on said grid to permit said tube to pass ignition current therethrough said control means comprising a magnetic circuit including a permanent magnet and a coil in which impulses are generated.

3. In an ignition system for internal combustion engines, a source of ignition current, an electron discharge tube acting as a control valve for said ignition current, said tube including a grid, a grid circuit operatively connected to said grid to supply a potential thereto, and control means in said grid circuit for controlling the potential on said grid to normally render the tube inoperative to pass ignition current therethrough but said control means being operable to vary the potential on said grid to permit said tube to pass ignition current therethrough 'said control means comprising an electromagnetic rotatable impulse generator in series with said grid and operable in synchronism with said engine.

FRANZ DAUSINGER. 

